Hair dryer

ABSTRACT

A hair dryer comprises a fan (F) for generating an air flow, and a drying chamber (HC) having a hair inlet (II) into which hair can be guided by the air flow. A cross-section of the drying chamber (HC) has a first dimension in a first direction, which first dimension is at least 5 times larger than a second dimension in a second direction perpendicular to the first direction, wherein the first and second directions are perpendicular to a direction of the air flow. The drying chamber (HC) may be folded in that the drying chamber has a U-turn in the direction of the air flow. A first area of the cross-section of the drying chamber (HC) at the U-turn may be smaller than a second area of the cross-section in the middle between the hair inlet (II) and the U-turn. A hair inlet (II) of the drying chamber (HC) may be shaped to follow a contour of a user&#39;s head. The hair dryer may be arranged for heating hair from multiple sides. A wall of the drying chamber (HC) may be provided with a hydrophilic or water absorbing or water surface tension reducing material. The water absorbing material may be regenerated by means of hot air. The drying chamber (HC) may be openable, whereby the drying chamber can be cleaned. The hair dryer may have a sensor (MS) for sensing temperature and/or humidity of the air flow at an air outlet of the hair dryer, and a part of the air flow may be recirculated based on an output of the sensor (MS). The hair dryer may have a nozzle to channel hot air towards a user&#39;s scalp. A wall of the drying chamber (HC) may be shaped so as to style the hair and/or increase a contact area that is in contact with the hair.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,118,874A discloses a hair dryer having inner and outerducts connected at one end to a centrifugal fan and at the other end toa hood. The fan sucks air through the inner duct and blows it towardsaid hood through the outer duct. A grille for supporting long hair ispositioned in the inner duct so that air drawn toward the fan is drawnthrough any long hair on said grille.

KR20160024677A discloses a hair dryer for long hair, which accommodatesand dries long hair insulated from the outside to maximize dryingefficiency. The hair dryer comprises: a housing having a handle formedon the outer surface of one side and a hair accommodation space formedwith a predetermined depth, wherein hair can be introduced through anopening at the upper part to be accommodated; a blower installed on thelower part of the housing to suck and blow external air into the hairaccommodation space; a blowing induction part inducing the air blown bythe blower to the inner wall surface of the housing to blow the air tothe outer circumference of the hair accommodated in the hairaccommodation space; and a heating means installed on a side of theblower, which outlets air, to heat the blown air.

US2016150864A1 discloses a hair grooming system includes a vacuumcanister, a hose, and a hand-held unit. The hose is secured to and influid communication with the vacuum canister and the hand-held unit. Thehand-held unit includes a vacuum chamber. A mechanism for creating avacuum is positioned in the vacuum canister, and the vacuum iscommunicated to the vacuum chamber by the hose. The system can furtherinclude a heating element and a fan arranged to heat air and move theair into the vacuum chamber. In one embodiment disclosed herein, amethod for grooming hair includes the steps of placing a section of hairinto a vacuum chamber; drawing a vacuum to remove excess water from thehair; and applying heated air to the section of hair.

It is, inter alia, an object of the invention to provide an improvedhair dryer. The invention is defined by the independent claims.Advantageous embodiments are defined in the dependent claims.

A cross-section of the drying chamber has a first dimension in a firstdirection, which first dimension is at least 5 times larger than asecond dimension in a second direction perpendicular to the firstdirection, wherein the first and second directions are perpendicular toa direction of the air flow in the drying chamber. The drying chamber isthus oval or even flat. Compared to a drying chamber having a circularcross-section, the advantage is obtained that hair is spread over thewidth of the drying chamber so that it is more equally dried. With acircular drying chamber, hair in the middle of a hair strand will remainhumid while hair at the outside of a hair strand will be dry, and if thesettings are adjusted such that hair in the middle is also sufficientlydried, hair at the outside of the hair strand will be exposed to toomuch heat, which will damage the hair.

Preferably, the first dimension is at least 10 times larger than asecond dimension.

A compact hair dryer design is obtained if the drying chamber is foldedin that the drying chamber has a U-turn in the direction of the airflow.

If a first area of the cross-section of the drying chamber at the U-turnis smaller than a second area of the cross-section in the middle betweenthe hair inlet and the U-turn, the air speed is locally increased whichfacilitates hair entering the device. With a smaller cross-section, itis additionally possible to increase the radius of the turns, whichagain makes it easier for the hair to make the U-turn withoutdeformations or undesired curls.

A more satisfactory hair drying experience is obtained if the hair dryeris arranged for heating hair from multiple sides.

The drying speed is also increased if a wall of the drying chamber isprovided with a hydrophilic or water absorbing or water surface tensionreducing material.

If the water absorbing material can be regenerated by means of hot air,the material can be used multiple times.

If the drying chamber is openable, the drying chamber can be cleaned.

If the hair dryer has a sensor for sensing temperature and/or humidityof the air flow at an air outlet of the hair dryer, and a part of theair flow is recirculated based on an output of the sensor, the airflowcan be controlled to get best results in terms of speed and hair feel,and it may become possible to do with less heater power.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section of an embodiment of a hair dryer accordingto the invention.

FIG. 2 shows another view of a hair dryer according to the invention.

DESCRIPTION OF EMBODIMENTS

As best seen in FIG. 2 , an inlet I1 for hair and cold air is wide, likea letter box sleeve. The wide inlet I1 of a drying chamber spreads hairevenly, thereby preventing hair in the middle of a tress from being notdried well. A rounded curve at the hair inlet I1 bends the hair into thedevice, based on the coanda effect. In preferred embodiments, the sizeof the hair inlet I1 ranges from 5×50 mm to 20×250 mm. In a practicalexample, the inlet I1 is 10×120 mm.

While the hair inlet I1 may be straight, in a preferred embodiment, theshape of the hair inlet I1 follows a contour of a user's head to allowmore hair to enter the drying chamber. The hair inlet I1 may thus becurved. In an alternative embodiment, the hair inlet I1 may be V-shaped.

In the embodiments shown, the drying chamber is formed by a folded hairchannel HC in which the hair will go in (downwards), then around thefirst round edge E1 U-turn up, and then around the second round edge E2U-turn down. In this way, a 60 cm long hair path as is needed forcustomers with long hair, can be fit into a compact device that is onlyabout 20 cm high. At the edges E1 and E2, a cross-sectional area can beless than in the idle between the edges so as to locally increase theair speed to help pull the hair through the U-turn, and to ensure thatthe U-turns are rounder, which also helps to allow hair to pass theU-turns in the hair channel HC. In a less complex embodiment, the dryingchamber has only one U-turn.

The inner wall of the drying chamber can be equipped with dimples as theairflow is defined and dimples may reduce drag. Dimples also help toimprove the heat exchange.

Preferably, a wall of the drying chamber HC is shaped so as to style thehair and/or increase a contact area that is in contact with the hair.The hair channel HC may contain ribs to spread the hairs or even stylethe hair, and may contain swirl ribs which can be set to create a curleffect. If the walls of the hair channel are hot, such ribs increase acontact area that is in contact with the hair, thereby speeding up thedrying process.

At the end of the drying chamber, a filter FT prevents hairs from goinginto a fan F. The filter FT is preferably removable so as to allow forcleaning.

The suction fan F can be set on flow, strong and weak. The fan F shouldbe able to handle a minimal amount of water/moisture. The fan F mayproduce an air flow of between 5 and 40 l/s, preferably between about 18to 20 l/s; fans as used in some vacuum cleaners may be suitable for thispurpose. Preferably, a single motor/fan unit is used to create suctionthat will not only pull hair into the hair channel HC but also pull airthrough or along a heater HT into the hair channel HC.

In the shown embodiments, heated air is only provided from one side(i.e. from the right side in the drawings) to the hair that has enteredthe hair dryer. In another embodiment, heated air is provided from bothleft and right sides to the hair.

In the shown embodiments, the heater HT is shown to the right of thefolded hair channel HC. In other embodiments, the heater HT is placedelsewhere, e.g. at the bottom, or before or after the folded hairchannel as shown in FIG. 1 from the viewpoint of a person looking atFIG. 1 .

Alternatively and/or additionally to a suction fan F at the end of thehair channel HC that sucks hair into the hair channel, it is possible tohave a fan in the separate channel in which a heater HT is placed so asto create an air flow in the hair channel HC that guides hair into thehair channel.

As shown in our co-pending application EP 20173773.1 (attorneys' ref.:2020PF00319), the hair channel HC may have multiple hot air inlets alongits trajectory so as to ensure that the heat is more evenly distributedover the hair length so as to ensure a more even drying rate.

After the fan F there is an outlet O for humid air. If the hair dryer isprovided with a heater HT, the outlet air is warm and could be used todry the scalp. To that end, the outlet air should be directed towardsthe scalp.

Just before the filter FT, or between the filter FT and the fan F, therecan be a sensor MS to measure the moisture and/or temperature, linked tothe dryness of the hair. Depending on the readings from the sensor MS,some outlet air from the fan F may be rechanneled by a valve V2 towardsthe heater HT to ensure an air flow along the heater HT. Thisrecirculation may save energy (as the heat in the outlet air is notwasted but reused), which is particularly important for abattery-operated hair dryer. Yet, the air flow should allow for asufficient cooling of the heater HT. However, the recirculated air mayhave too much moisture to ensure that hair is dried in a satisfactoryway, so that if the sensor MS indicates that the air contains too muchmoisture, the air is not recirculated or only to a limited extent bysuitably controlling the valve V2. Depending on the readings from themoisture sensor MS, the hair dryer may indicate that the hair has beensufficiently dried, e.g. by beep signals.

If the heater HT is of a type that provides hot air to the hair, anoutlet of an air channel in which the heater HT is located, is placed atthe beginning of the hair channel HC, near the hair inlet I1. The airflow is balanced in such a way that enough air goes through the heaterto cool it and provide hot air to the hair. For example, about 50% ofthe air flow in the hair channel comes through the hair inlet, and about50% of the air flow in the hair channel comes from the channel (orchannels) in which the heater HT is positioned. Once the hair is closingthe hair inlet I1, the hot air ratio will increase. To ensure that asufficient amount of hot air is applied to the hair, a mechanism may beprovided to make the inlet I1 narrower once hair has entered the hairdryer, so that less cold air can enter the hair dryer through the inletI1. The air channel in which the heater HT is located may have its owninlet 12 for cold air in case there is no recirculation or insufficientrecirculation to ensure a sufficiently large airflow to cool the heaterHT and to provide a sufficient amount of hot air to the hair.

The heater HT can be controlled with a temperature switch. Thetemperature in the hair channel HC is preferably around 70˜100° C. Theheater HT may be a conventional (coil/ceramic) heater. The heater HT mayhave a power between 1000 W and 2500 W, such as a 1600 W or 2100 Wheater as used in conventional hair dryers.

If the heater HT is element-based, it can be placed along the hairchannel walls (e.g. a PTC heater/thin film heater). Again the surfacecan be provided with dimples to improve heat exchange. The heatercapacity can be less as all the heat flows along the hairs. A lowerheater wattage allows for a cordless, i.e. battery-operated device, asefficiency is better.

If the heater HT is light-radiation based, the entire hair channel HCcan be made transparent/mirrored to allow all the light passing throughand multiple times hit the hair. As disclosed in our co-pendingapplication WO2019/048357 (attorneys' ref: 2017PF02405), heat generatedby the LED units is preferably reused to heat the hair, e.g. by means ofan airflow that has passed the LED units or cooling bodies thereof.

If the heater HT is off and cooled down, as indicated by a temperaturesensor TS1, a valve V1 at the outlet of the hot air channel can beclosed so as to ensure that the suction through the inlet I isincreased.

There can be an IR sensor inside to measure the temp of the hair. Othersensors can be added, such as a camera allowing for settings of the fanF and/or heater HT and/or any ionizer to be adjusted based on ananalysis (possibly involving artificial intelligence) of images taken bythe camera.

If the hair dryer is battery-operated, the battery can be cooled by theair in the hair channel HC.

The hair dryer can be connected with IoT, e.g. the device may have aBluetooth connection to a smartphone having an app so that the devicecan be controlled by means of the smartphone, which makes particularlysense if the hair dryer is a tabletop device placed on a desk at theback of the user while the hair dryer is in use so that any controls onthe hair dryer cannot be reached. The device may have a UI. The hairdryer can be handheld with or without power cord. The device can be puton a desk and positioned under an angle.

An inner wall of the hair channel HC is preferably provided with acovering of a water absorbing material for absorbing water and/or amaterial to break/reduce the surface tension of the water droplets so asto increase the dry rate. Preferably, the water absorbing material canbe regenerated by letting hot air pass the hair channel without hairbeing present.

The hair may alternatively be dried without applying hot air, viz. byusing ultrasound e.g. as described in EP 3416521 B1 (attorneys' ref.:2016PF00205).

When the hair is pulled out, hair health can be measured by measuringthe friction in a manner shown in our co-pending application WO2019/057575 (attorneys' ref: 2017PF02274).

In an embodiment, the hair dryer has a nozzle to channel hot air (e.g.outlet air) towards a user's scalp to dry the scalp while the hair isdried, which gives a spa-like experience.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. In the claims, any reference signsplaced between parentheses shall not be construed as limiting the claim.The word “comprising” does not exclude the presence of elements or stepsother than those listed in a claim. The word “a” or “an” preceding anelement does not exclude the presence of a plurality of such elements.Measures recited in mutually different dependent claims mayadvantageously be used in combination.

1. A hair dryer comprising: a fan for generating an air flow; and adrying chamber having a hair inlet into which hair can be guided by theair flow; wherein a cross-section of the drying chamber has a firstdimension in a first direction, which first dimension is at least 5times larger than a second dimension in a second direction perpendicularto the first direction, wherein both the first direction and the seconddirection are perpendicular to a direction of the air flow.
 2. A hairdryer as claimed in claim 1, wherein the first dimension is at least 10times larger than a second dimension.
 3. A hair dryer as claimed inclaim 1, wherein the drying chamber is folded in that the drying chamberhas a U-turn in the direction of the air flow.
 4. A hair dryer asclaimed in claim 3, wherein a first area of the cross-section of thedrying chamber at the U-turn is smaller than a second area of thecross-section in the middle between the hair inlet and the U-turn.
 5. Ahair dryer as claimed in claim 1, wherein the hair inlet of the dryingchamber is shaped to follow a contour of a user's head.
 6. A hair dryeras claimed in claim 1, wherein the hair dryer is arranged for heatinghair from multiple sides.
 7. A hair dryer as claimed in claim 1, whereina wall of the drying chamber is provided with a hydrophilic or waterabsorbing or water surface tension reducing material.
 8. A hair dryer asclaimed in claim 7, wherein the water absorbing material can beregenerated by means of hot air.
 9. A hair dryer as claimed in claim 1,wherein the drying chamber is openable, whereby the drying chamber canbe cleaned.
 10. A hair dryer as claimed in claim 1, wherein the hairdryer has a sensor for sensing temperature and/or humidity of the airflow at an air outlet of the hair dryer, and wherein a part of the airflow is recirculated based on an output of the sensor.
 11. A hair dryeras claimed in claim 1, wherein the hair dryer has a nozzle to channelhot air towards a user's scalp.
 12. A hair dryer as claimed in claim 1,wherein a wall of the drying chamber is shaped so as to style the hairand/or increase a contact area that is in contact with the hair.